Research

I. Monovalent gold for nanophotonics at visible wavelengthsMonovalent gold nanoparticles serve as constituents of artificial molecules, much like atoms form the basis for molecules. We use bottom-up self-assembly to build 3D assemblies of plasmonic nanoparticles in high yield to make nanophotonic building blocks for the manipulation of visible wavelengths. To this end, we exploit the efficacy of quantitative, orthogonal chemical reactions to selectively and efficiently link plasmonic nanoparticles at length scales that are challenging for current lithographic techniques. Some of the potential applications are:

Metamaterials. The optical properties of metamaterials depend on the interaction of its sub-wavelength building blocks with light, as opposed to atomic or molecular constituents that usually define the properties of a material. Particles will be templated with rigid organic scaffolds to generate assemblies with higher order multipoles, some of which will satisfy the symmetry requirements for electric and magnetic dipoles. The introduction of a magnetic response in materials at visible wavelengths will allow light to be manipulated in an unprecedented manner.

Vacuum Rabi Splitting. The interaction of a single emitter with a plasmonic nanoantenna dimer in the strong coupling regime can give rise to half-matter half-light modes with implication for quantum logic, coherent control of single photons, etc.

Antenna- enhanced fluorescence and Raman Scattering.

Asymmetric enantioselective synthesis.

II. Single molecule studies of the nanoparticle-ligand interfaceTo date, characterization of molecular species on nanocrystal surfaces remains a challenge. The construction of complex sensing systems with specific, reproducible responses to analytes; or the solution based processing of nanocrystals for efficient light emitting diodes or flexible transistors and solar cells, hinges on a complete understanding of the nanocrystal-ligand interface. We intend to use super-resolution fluorescence microscopy to quantitatively and spatially characterize the organic moieties on colloidally synthesized semiconductor nanocrystals; and to examine the effect of ligands on nanoparticle photophysics. The synthesis of labeled ligands that consist of organic fluorophores covalently bound to a nanocrystal binding group will enable the localization of ligands on nanocrystals in a quantitative manner, at millisecond timescales, at the single particle level. Such spatial and temporal resolution will provide a deep understanding of the effect of ligands on nanocrystal photophysics.

Join the group! Prospective graduate students and postdocs are welcome.